Added dictionary plugin and switched from a Mutex to an RwLock in the anyrun_plugin crate

This change means that `get_matches` no longer has access to a mutable version of the
state of the plugin. A redesign is needed to allow for this if needed.

plugins/randr/src/lib.rs

@@ -98,7 +98,7 @@ pub fn handler(_match: Match, state: &mut State) -> HandleResult {
     }
 }
 
-pub fn get_matches(input: RString, state: &mut State) -> RVec<Match> {
+pub fn get_matches(input: RString, state: &State) -> RVec<Match> {
     if !input.starts_with(&state.config.prefix) {
         return RVec::new();
     }